/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
using System;
using java = biz.ritter.javapi;

using org.apache.commons.codec;

namespace org.apache.commons.codec.language
{

    /**
     * Encodes a string into a Refined Soundex value. A refined soundex code is
     * optimized for spell checking words. Soundex method originally developed by
     * <CITE>Margaret Odell</CITE> and <CITE>Robert Russell</CITE>.
     * 
     * @author Apache Software Foundation
     * @version $Id: RefinedSoundex.java 797690 2009-07-24 23:28:35Z ggregory $
     */
    public class RefinedSoundex : StringEncoder
    {

        /**
         * @since 1.4
         */
        public static readonly String US_ENGLISH_MAPPING_STRING = "01360240043788015936020505";

        /**
          * RefinedSoundex is *refined* for a number of reasons one being that the
          * mappings have been altered. This implementation contains default
          * mappings for US English.
          */
        public static readonly char[] US_ENGLISH_MAPPING = US_ENGLISH_MAPPING_STRING.toCharArray();

        /**
         * Every letter of the alphabet is "mapped" to a numerical value. This char
         * array holds the values to which each letter is mapped. This
         * implementation contains a default map for US_ENGLISH
         */
        private readonly char[] soundexMapping;

        /**
         * This static variable contains an instance of the RefinedSoundex using
         * the US_ENGLISH mapping.
         */
        public static readonly RefinedSoundex US_ENGLISH = new RefinedSoundex();

        /**
        * Creates an instance of the RefinedSoundex object using the default US
        * English mapping.
        */
        public RefinedSoundex()
        {
            this.soundexMapping = US_ENGLISH_MAPPING;
        }

        /**
         * Creates a refined soundex instance using a custom mapping. This
         * constructor can be used to customize the mapping, and/or possibly
         * provide an internationalized mapping for a non-Western character set.
         * 
         * @param mapping
         *                  Mapping array to use when finding the corresponding code for
         *                  a given character
         */
        public RefinedSoundex(char[] mapping)
        {
            this.soundexMapping = new char[mapping.Length];
            java.lang.SystemJ.arraycopy(mapping, 0, this.soundexMapping, 0, mapping.Length);
        }

        /**
         * Creates a refined Soundex instance using a custom mapping. This constructor can be used to customize the mapping,
         * and/or possibly provide an internationalized mapping for a non-Western character set.
         * 
         * @param mapping
         *            Mapping string to use when finding the corresponding code for a given character
         * @since 1.4
         */
        public RefinedSoundex(String mapping)
        {
            this.soundexMapping = mapping.toCharArray();
        }

        /**
         * Returns the number of characters in the two encoded Strings that are the
         * same. This return value ranges from 0 to the length of the shortest
         * encoded String: 0 indicates little or no similarity, and 4 out of 4 (for
         * example) indicates strong similarity or identical values. For refined
         * Soundex, the return value can be greater than 4.
         * 
         * @param s1
         *                  A String that will be encoded and compared.
         * @param s2
         *                  A String that will be encoded and compared.
         * @return The number of characters in the two encoded Strings that are the
         *             same from 0 to to the length of the shortest encoded String.
         * 
         * @see SoundexUtils#difference(StringEncoder,String,String)
         * @see <a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/tsqlref/ts_de-dz_8co5.asp">
         *          MS T-SQL DIFFERENCE</a>
         * 
         * @throws EncoderException
         *                  if an error occurs encoding one of the strings
         * @since 1.3
         */
        public int difference(String s1, String s2)
        {// throws EncoderException {
            return SoundexUtils.difference(this, s1, s2);
        }

        /**
         * Encodes an Object using the refined soundex algorithm. This method is
         * provided in order to satisfy the requirements of the Encoder interface,
         * and will throw an EncoderException if the supplied object is not of type
         * java.lang.String.
         * 
         * @param pObject
         *                  Object to encode
         * @return An object (or type java.lang.String) containing the refined
         *             soundex code which corresponds to the String supplied.
         * @throws EncoderException
         *                  if the parameter supplied is not of type java.lang.String
         */
        public Object encode(Object pObject)
        {// throws EncoderException {
            if (pObject is java.lang.StringJ) pObject = ((java.lang.StringJ)pObject).ToString();
            if (!(pObject is String))
            {
                throw new EncoderException("Parameter supplied to RefinedSoundex encode is not of type java.lang.String");
            }
            return soundex((String)pObject);
        }

        /**
         * Encodes a String using the refined soundex algorithm.
         * 
         * @param pString
         *                  A String object to encode
         * @return A Soundex code corresponding to the String supplied
         */
        public String encode(String pString)
        {
            return soundex(pString);
        }

        /**
         * Returns the mapping code for a given character. The mapping codes are
         * maintained in an internal char array named soundexMapping, and the
         * default values of these mappings are US English.
         * 
         * @param c
         *                  char to get mapping for
         * @return A character (really a numeral) to return for the given char
         */
        char getMappingCode(char c)
        {
            if (!java.lang.Character.isLetter(c))
            {
                return '\u0000';
            }
            return this.soundexMapping[java.lang.Character.toUpperCase(c) - 'A'];
        }

        /**
         * Retreives the Refined Soundex code for a given String object.
         * 
         * @param str
         *                  String to encode using the Refined Soundex algorithm
         * @return A soundex code for the String supplied
         */
        public String soundex(String str)
        {
            if (str == null)
            {
                return null;
            }
            str = SoundexUtils.clean(str);
            if (str.length() == 0)
            {
                return str;
            }

            java.lang.StringBuffer sBuf = new java.lang.StringBuffer();
            sBuf.append(str.charAt(0));

            char last, current;
            last = '*';

            for (int i = 0; i < str.length(); i++)
            {

                current = getMappingCode(str.charAt(i));
                if (current == last)
                {
                    continue;
                }
                else if (current != 0)
                {
                    sBuf.append(current);
                }

                last = current;

            }

            return sBuf.toString();
        }
    }
}